[Qemu-devel] [PATCH] Clear RF on SYSCALL instruction

[Roman Kapl <rka@sysgo.com>]

From: Rudolf Marek <rudolf.marek@sysgo.com>

Fix the SYSCALL instruction in 64-bit (long mode). The RF flag
should be cleared in R11 as well as in the RFLAGS. Intel
and AMD CPUs behave same. AMD has this documented in the
APM vol 3.

Signed-off-by: Roman Kapl <rka@sysgo.com>
Signed-off-by: Rudolf Marek <rudolf.marek@sysgo.com>
---
 target/i386/seg_helper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/i386/seg_helper.c b/target/i386/seg_helper.c
index 33714bc6e1..63e265cb38 100644
--- a/target/i386/seg_helper.c
+++ b/target/i386/seg_helper.c
@@ -991,11 +991,11 @@ void helper_syscall(CPUX86State *env, int next_eip_addend)
         int code64;
 
         env->regs[R_ECX] = env->eip + next_eip_addend;
-        env->regs[11] = cpu_compute_eflags(env);
+        env->regs[11] = cpu_compute_eflags(env) & ~RF_MASK;
 
         code64 = env->hflags & HF_CS64_MASK;
 
-        env->eflags &= ~env->fmask;
+        env->eflags &= ~(env->fmask | RF_MASK);
         cpu_load_eflags(env, env->eflags, 0);
         cpu_x86_load_seg_cache(env, R_CS, selector & 0xfffc,
                            0, 0xffffffff,
-- 
2.11.0